The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Catalytic converters are used in an exhaust system of an internal combustion engine (ICE) to reduce emissions. For example, a thee-way catalyst converter (TWC) reduces nitrogen oxide, carbon monoxide and hydrocarbons within an exhaust system. The three-way catalyst converter: converts nitrogen oxide to nitrogen and oxygen; converts carbon monoxide to carbon dioxide; and oxidizes unburnt hydrocarbons (HC) to produce carbon dioxide and water.
An average catalyst light-off temperature at which a catalytic converter typically begins to function is approximately 200-350° C. As a result, a catalytic converter does not function or provides minimal emission reduction during a warm up period that occurs upon a cold start up of an engine. Exhaust system temperatures are less than the catalyst light-off temperature during an engine cold start. During the warm up period, HC emissions may not be effectively processed by the catalytic converter.
A hydrocarbon adsorber may be used to trap HC during the warm up period. Hydrocarbon adsorbers typically trap HC when at a temperature approximately less than 200° C. and release trapped hydrocarbons at temperatures greater than or equal to approximately 200° C.
During certain driving cycles, such as start/stop applications (short engine operation periods) and short trips, hydrocarbon adsorber regeneration time may be limited. For this reason, regeneration of a hydrocarbon adsorber may not be completed, which can cause low temperature fouling of the hydrocarbon adsorber. This degrades emission performance during, for example, an engine cold start.